With Nitrogen Nucleophiles

Reactions with Nitrogen Nucleophiles. Treatment of an epoxide with one of the diethylaluminium amides [153 = Et, CHjPh, or CH2CH=CH2  

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The polymerization of ethyleneimine (16,354—357) is started by a catalyticaHy active reagent (H or a Lewis acid), which converts the ethyleneimine into a highly electrophilic initiator molecule. The initiator then reacts with nitrogen nucleophiles, such as the ethyleneimine monomer and the subsequendy formed oligomers, to produce a branched polymer, which contains primary, secondary, and tertiary nitrogen atoms in random ratios. Termination takes place by intramolecular macrocycle formation. 

Reaction at position 4 of perfluotopyndme thus occurs readily with nitrogen nucleophiles, as exemplified by its reactions with sodium azide and with hydroxyl-amme [75, 76] (equation 39)... 

Phosphorus nucleophiles have received little attention compared with nitrogen nucleophiles in reactions with fluonnated systems Yields with phosphorus nucleophiles are sometimes low, but interesting materials are obtained [80, 81] (equations 42 and 43). 

With Nitrogen Nucleophiles Aziridine-2-carboxylates react with primary and secondary amines, including anilines, to give a, 3-bisamino carboxylates [71, 113]. As an example, treatment of aziridine 153 (Scheme 3.55) with diethylamine in methylene chloride afforded compound 154 in 89% yield after chromatographic separation. 

The l-imino-lff-2-benzopyran (13) ring opens on treatment with nitrogen nucleophiles. Different modes of recyclisation are possible and (13) is therefore a source of a variety of -heterocycles <96AJC485>. 

B. Palladium-catalyzed substitution with nitrogen nucleophiles 4d... 

Part of the great efficiency of the intramolecular reactions of [26] and [27] is undoubtedly due to the correct alignment of the rigidly held nucleophile and carbonyl group. Molecular models show that in one of the conformations of [27] in which steric interactions are minimized, the phenoxide ion is immediately adjacent to the carbonyl group and in an excellent position for perpendicular attack (Bender, 1960) but other factors must also be important. Correct orientation would not explain why anionic nucleophiles are superior to neutral nucleophiles. Extensive studies have not been carried out with nitrogen nucleophiles in carbamate ester hydrolysis, but Hegarty and Frost (1972) found that carbamate [29] underwent elimination to an isocyanate. This can be contrasted with the... 

Thermally insensitive explosives from halide displacement with nitrogen nucleophiles... 

V-Alkoxy-V-chloroureas (77) have also been reacted with nitrogen nucleophiles resulting in Sat2 displacement of chloride. The products suggest that the reaction proceeds via an unstable V-alkoxy-V-amino intermediate (78), which under the influence of hydrochloric acid formed in the reaction, decomposed as illustrated to diaminomethane (79) and urea (80) (Scheme 15), although the exact mechanism is unclear . 

In general, the reaction of unsaturated 5(4//)-oxazolones 497 with nitrogen nucleophiles effects ring opening to give the corresponding unsaturated acylamino amides 498 (Scheme 7.158). Depending on the nucleophile, for example, amines, hydrazines, oximes, and so on, the products obtained can be cyclized and this process allows the synthesis of a wide variety of new heterocyclic compounds. 

There are a number of comprehensive studies reported of the reactions of a particular unsaturated oxazolone with nitrogen nucleophiles. On the other hand, unsaturated 5(4/f)-oxazolones react with a variety of amines to yield acylamino amides with interesting agrochemical properties. ... 

Unsaturated 5(4//)-oxazolones derived from aromatic and heterocyclic aldehydes including phthalic anhydride/ antipyrine/ " chromone/ indoles/ pyridines/" ° quinolines/" diazines/" benzoxazoles/" and benzimidazoles " " have been prepared. Reaction with nitrogen nucleophiles and subsequent cycliza-tion leads to the expected 5(477)-imidazolones. 

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